This invention relates to a waste water treatment method and electrolytic apparatus for practicing the method by which impurities in water, particularly heavy metal ions, organic materials, suspended substances, silica, coloring matter, and like impurities contained in water for industrial use and industrial waste water are electrolytically separated and removed.
In a waste water treatment method of this kind depending on electrolytic separation means known heretofore, treated water is obtained by causing the impurities within the waste water to be caught in a floc of a metal hydroxide formed by the dissolution of the anode metal in the form of an aluminum plate or an iron plate and separating the impurities by causing the floc to settle or sediment under the force of gravity. By this method, however, the floc is of a small size and requires a long settling time in the gravity settling step. Moreover, the sedimentation volume is large and the water content of the sediment or sludge is high. Accordingly, it takes time to desiccate the sludge.
In this known electrolytic treatment method, furthermore, the power efficiency drops after the long operation because of the formation of oxide film on or adhesion of scales to the anode. Still another problem is that the anode falls off before it is completely consumed and is therefore not effectively utilized.